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qemu/hw/virtio-blk.c
Christian Borntraeger 69b302b204 virtio-blk: fix unplug + virsh reboot 
virtio-blk registers a vmstate change handler. Unfortunately this
handler is not unregistered on unplug, leading to some random
crashes if the system is restarted, e.g. via virsh reboot.
Lets unregister the vmstate change handler if the device is removed.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-03-04 09:54:16 +01:00

711 lines
19 KiB
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/*
* Virtio Block Device
*
* Copyright IBM, Corp. 2007
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "qemu-common.h"
#include "qemu/error-report.h"
#include "trace.h"
#include "hw/block-common.h"
#include "sysemu/blockdev.h"
#include "virtio-blk.h"
#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
#include "hw/dataplane/virtio-blk.h"
#endif
#include "scsi-defs.h"
#ifdef __linux__
# include <scsi/sg.h>
#endif
typedef struct VirtIOBlock
{
VirtIODevice vdev;
BlockDriverState *bs;
VirtQueue *vq;
void *rq;
QEMUBH *bh;
BlockConf *conf;
VirtIOBlkConf *blk;
unsigned short sector_mask;
DeviceState *qdev;
VMChangeStateEntry *change;
#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
VirtIOBlockDataPlane *dataplane;
#endif
} VirtIOBlock;
static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
{
return (VirtIOBlock *)vdev;
}
typedef struct VirtIOBlockReq
{
VirtIOBlock *dev;
VirtQueueElement elem;
struct virtio_blk_inhdr *in;
struct virtio_blk_outhdr *out;
struct virtio_scsi_inhdr *scsi;
QEMUIOVector qiov;
struct VirtIOBlockReq *next;
BlockAcctCookie acct;
} VirtIOBlockReq;
static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
{
VirtIOBlock *s = req->dev;
trace_virtio_blk_req_complete(req, status);
stb_p(&req->in->status, status);
virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in));
virtio_notify(&s->vdev, s->vq);
}
static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
bool is_read)
{
BlockErrorAction action = bdrv_get_error_action(req->dev->bs, is_read, error);
VirtIOBlock *s = req->dev;
if (action == BDRV_ACTION_STOP) {
req->next = s->rq;
s->rq = req;
} else if (action == BDRV_ACTION_REPORT) {
virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
bdrv_acct_done(s->bs, &req->acct);
g_free(req);
}
bdrv_error_action(s->bs, action, is_read, error);
return action != BDRV_ACTION_IGNORE;
}
static void virtio_blk_rw_complete(void *opaque, int ret)
{
VirtIOBlockReq *req = opaque;
trace_virtio_blk_rw_complete(req, ret);
if (ret) {
bool is_read = !(ldl_p(&req->out->type) & VIRTIO_BLK_T_OUT);
if (virtio_blk_handle_rw_error(req, -ret, is_read))
return;
}
virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
bdrv_acct_done(req->dev->bs, &req->acct);
g_free(req);
}
static void virtio_blk_flush_complete(void *opaque, int ret)
{
VirtIOBlockReq *req = opaque;
if (ret) {
if (virtio_blk_handle_rw_error(req, -ret, 0)) {
return;
}
}
virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
bdrv_acct_done(req->dev->bs, &req->acct);
g_free(req);
}
static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
{
VirtIOBlockReq *req = g_malloc(sizeof(*req));
req->dev = s;
req->qiov.size = 0;
req->next = NULL;
return req;
}
static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)
{
VirtIOBlockReq *req = virtio_blk_alloc_request(s);
if (req != NULL) {
if (!virtqueue_pop(s->vq, &req->elem)) {
g_free(req);
return NULL;
}
}
return req;
}
static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
{
#ifdef __linux__
int ret;
int i;
#endif
int status = VIRTIO_BLK_S_OK;
/*
* We require at least one output segment each for the virtio_blk_outhdr
* and the SCSI command block.
*
* We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr
* and the sense buffer pointer in the input segments.
*/
if (req->elem.out_num < 2 || req->elem.in_num < 3) {
virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
g_free(req);
return;
}
/*
* The scsi inhdr is placed in the second-to-last input segment, just
* before the regular inhdr.
*/
req->scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base;
if (!req->dev->blk->scsi) {
status = VIRTIO_BLK_S_UNSUPP;
goto fail;
}
/*
* No support for bidirection commands yet.
*/
if (req->elem.out_num > 2 && req->elem.in_num > 3) {
status = VIRTIO_BLK_S_UNSUPP;
goto fail;
}
#ifdef __linux__
struct sg_io_hdr hdr;
memset(&hdr, 0, sizeof(struct sg_io_hdr));
hdr.interface_id = 'S';
hdr.cmd_len = req->elem.out_sg[1].iov_len;
hdr.cmdp = req->elem.out_sg[1].iov_base;
hdr.dxfer_len = 0;
if (req->elem.out_num > 2) {
/*
* If there are more than the minimally required 2 output segments
* there is write payload starting from the third iovec.
*/
hdr.dxfer_direction = SG_DXFER_TO_DEV;
hdr.iovec_count = req->elem.out_num - 2;
for (i = 0; i < hdr.iovec_count; i++)
hdr.dxfer_len += req->elem.out_sg[i + 2].iov_len;
hdr.dxferp = req->elem.out_sg + 2;
} else if (req->elem.in_num > 3) {
/*
* If we have more than 3 input segments the guest wants to actually
* read data.
*/
hdr.dxfer_direction = SG_DXFER_FROM_DEV;
hdr.iovec_count = req->elem.in_num - 3;
for (i = 0; i < hdr.iovec_count; i++)
hdr.dxfer_len += req->elem.in_sg[i].iov_len;
hdr.dxferp = req->elem.in_sg;
} else {
/*
* Some SCSI commands don't actually transfer any data.
*/
hdr.dxfer_direction = SG_DXFER_NONE;
}
hdr.sbp = req->elem.in_sg[req->elem.in_num - 3].iov_base;
hdr.mx_sb_len = req->elem.in_sg[req->elem.in_num - 3].iov_len;
ret = bdrv_ioctl(req->dev->bs, SG_IO, &hdr);
if (ret) {
status = VIRTIO_BLK_S_UNSUPP;
goto fail;
}
/*
* From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)
* clear the masked_status field [hence status gets cleared too, see
* block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED
* status has occurred. However they do set DRIVER_SENSE in driver_status
* field. Also a (sb_len_wr > 0) indicates there is a sense buffer.
*/
if (hdr.status == 0 && hdr.sb_len_wr > 0) {
hdr.status = CHECK_CONDITION;
}
stl_p(&req->scsi->errors,
hdr.status | (hdr.msg_status << 8) |
(hdr.host_status << 16) | (hdr.driver_status << 24));
stl_p(&req->scsi->residual, hdr.resid);
stl_p(&req->scsi->sense_len, hdr.sb_len_wr);
stl_p(&req->scsi->data_len, hdr.dxfer_len);
virtio_blk_req_complete(req, status);
g_free(req);
return;
#else
abort();
#endif
fail:
/* Just put anything nonzero so that the ioctl fails in the guest. */
stl_p(&req->scsi->errors, 255);
virtio_blk_req_complete(req, status);
g_free(req);
}
typedef struct MultiReqBuffer {
BlockRequest blkreq[32];
unsigned int num_writes;
} MultiReqBuffer;
static void virtio_submit_multiwrite(BlockDriverState *bs, MultiReqBuffer *mrb)
{
int i, ret;
if (!mrb->num_writes) {
return;
}
ret = bdrv_aio_multiwrite(bs, mrb->blkreq, mrb->num_writes);
if (ret != 0) {
for (i = 0; i < mrb->num_writes; i++) {
if (mrb->blkreq[i].error) {
virtio_blk_rw_complete(mrb->blkreq[i].opaque, -EIO);
}
}
}
mrb->num_writes = 0;
}
static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb)
{
bdrv_acct_start(req->dev->bs, &req->acct, 0, BDRV_ACCT_FLUSH);
/*
* Make sure all outstanding writes are posted to the backing device.
*/
virtio_submit_multiwrite(req->dev->bs, mrb);
bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req);
}
static void virtio_blk_handle_write(VirtIOBlockReq *req, MultiReqBuffer *mrb)
{
BlockRequest *blkreq;
uint64_t sector;
sector = ldq_p(&req->out->sector);
bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_WRITE);
trace_virtio_blk_handle_write(req, sector, req->qiov.size / 512);
if (sector & req->dev->sector_mask) {
virtio_blk_rw_complete(req, -EIO);
return;
}
if (req->qiov.size % req->dev->conf->logical_block_size) {
virtio_blk_rw_complete(req, -EIO);
return;
}
if (mrb->num_writes == 32) {
virtio_submit_multiwrite(req->dev->bs, mrb);
}
blkreq = &mrb->blkreq[mrb->num_writes];
blkreq->sector = sector;
blkreq->nb_sectors = req->qiov.size / BDRV_SECTOR_SIZE;
blkreq->qiov = &req->qiov;
blkreq->cb = virtio_blk_rw_complete;
blkreq->opaque = req;
blkreq->error = 0;
mrb->num_writes++;
}
static void virtio_blk_handle_read(VirtIOBlockReq *req)
{
uint64_t sector;
sector = ldq_p(&req->out->sector);
bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_READ);
trace_virtio_blk_handle_read(req, sector, req->qiov.size / 512);
if (sector & req->dev->sector_mask) {
virtio_blk_rw_complete(req, -EIO);
return;
}
if (req->qiov.size % req->dev->conf->logical_block_size) {
virtio_blk_rw_complete(req, -EIO);
return;
}
bdrv_aio_readv(req->dev->bs, sector, &req->qiov,
req->qiov.size / BDRV_SECTOR_SIZE,
virtio_blk_rw_complete, req);
}
static void virtio_blk_handle_request(VirtIOBlockReq *req,
MultiReqBuffer *mrb)
{
uint32_t type;
if (req->elem.out_num < 1 || req->elem.in_num < 1) {
error_report("virtio-blk missing headers");
exit(1);
}
if (req->elem.out_sg[0].iov_len < sizeof(*req->out) ||
req->elem.in_sg[req->elem.in_num - 1].iov_len < sizeof(*req->in)) {
error_report("virtio-blk header not in correct element");
exit(1);
}
req->out = (void *)req->elem.out_sg[0].iov_base;
req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base;
type = ldl_p(&req->out->type);
if (type & VIRTIO_BLK_T_FLUSH) {
virtio_blk_handle_flush(req, mrb);
} else if (type & VIRTIO_BLK_T_SCSI_CMD) {
virtio_blk_handle_scsi(req);
} else if (type & VIRTIO_BLK_T_GET_ID) {
VirtIOBlock *s = req->dev;
/*
* NB: per existing s/n string convention the string is
* terminated by '\0' only when shorter than buffer.
*/
strncpy(req->elem.in_sg[0].iov_base,
s->blk->serial ? s->blk->serial : "",
MIN(req->elem.in_sg[0].iov_len, VIRTIO_BLK_ID_BYTES));
virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
g_free(req);
} else if (type & VIRTIO_BLK_T_OUT) {
qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
req->elem.out_num - 1);
virtio_blk_handle_write(req, mrb);
} else if (type == VIRTIO_BLK_T_IN || type == VIRTIO_BLK_T_BARRIER) {
/* VIRTIO_BLK_T_IN is 0, so we can't just & it. */
qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
req->elem.in_num - 1);
virtio_blk_handle_read(req);
} else {
virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
g_free(req);
}
}
static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOBlock *s = to_virtio_blk(vdev);
VirtIOBlockReq *req;
MultiReqBuffer mrb = {
.num_writes = 0,
};
#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
/* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
* dataplane here instead of waiting for .set_status().
*/
if (s->dataplane) {
virtio_blk_data_plane_start(s->dataplane);
return;
}
#endif
while ((req = virtio_blk_get_request(s))) {
virtio_blk_handle_request(req, &mrb);
}
virtio_submit_multiwrite(s->bs, &mrb);
/*
* FIXME: Want to check for completions before returning to guest mode,
* so cached reads and writes are reported as quickly as possible. But
* that should be done in the generic block layer.
*/
}
static void virtio_blk_dma_restart_bh(void *opaque)
{
VirtIOBlock *s = opaque;
VirtIOBlockReq *req = s->rq;
MultiReqBuffer mrb = {
.num_writes = 0,
};
qemu_bh_delete(s->bh);
s->bh = NULL;
s->rq = NULL;
while (req) {
virtio_blk_handle_request(req, &mrb);
req = req->next;
}
virtio_submit_multiwrite(s->bs, &mrb);
}
static void virtio_blk_dma_restart_cb(void *opaque, int running,
RunState state)
{
VirtIOBlock *s = opaque;
if (!running) {
return;
}
if (!s->bh) {
s->bh = qemu_bh_new(virtio_blk_dma_restart_bh, s);
qemu_bh_schedule(s->bh);
}
}
static void virtio_blk_reset(VirtIODevice *vdev)
{
#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
VirtIOBlock *s = to_virtio_blk(vdev);
if (s->dataplane) {
virtio_blk_data_plane_stop(s->dataplane);
}
#endif
/*
* This should cancel pending requests, but can't do nicely until there
* are per-device request lists.
*/
bdrv_drain_all();
}
/* coalesce internal state, copy to pci i/o region 0
*/
static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
{
VirtIOBlock *s = to_virtio_blk(vdev);
struct virtio_blk_config blkcfg;
uint64_t capacity;
int blk_size = s->conf->logical_block_size;
bdrv_get_geometry(s->bs, &capacity);
memset(&blkcfg, 0, sizeof(blkcfg));
stq_raw(&blkcfg.capacity, capacity);
stl_raw(&blkcfg.seg_max, 128 - 2);
stw_raw(&blkcfg.cylinders, s->conf->cyls);
stl_raw(&blkcfg.blk_size, blk_size);
stw_raw(&blkcfg.min_io_size, s->conf->min_io_size / blk_size);
stw_raw(&blkcfg.opt_io_size, s->conf->opt_io_size / blk_size);
blkcfg.heads = s->conf->heads;
/*
* We must ensure that the block device capacity is a multiple of
* the logical block size. If that is not the case, lets use
* sector_mask to adopt the geometry to have a correct picture.
* For those devices where the capacity is ok for the given geometry
* we dont touch the sector value of the geometry, since some devices
* (like s390 dasd) need a specific value. Here the capacity is already
* cyls*heads*secs*blk_size and the sector value is not block size
* divided by 512 - instead it is the amount of blk_size blocks
* per track (cylinder).
*/
if (bdrv_getlength(s->bs) / s->conf->heads / s->conf->secs % blk_size) {
blkcfg.sectors = s->conf->secs & ~s->sector_mask;
} else {
blkcfg.sectors = s->conf->secs;
}
blkcfg.size_max = 0;
blkcfg.physical_block_exp = get_physical_block_exp(s->conf);
blkcfg.alignment_offset = 0;
blkcfg.wce = bdrv_enable_write_cache(s->bs);
memcpy(config, &blkcfg, sizeof(struct virtio_blk_config));
}
static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config)
{
VirtIOBlock *s = to_virtio_blk(vdev);
struct virtio_blk_config blkcfg;
memcpy(&blkcfg, config, sizeof(blkcfg));
bdrv_set_enable_write_cache(s->bs, blkcfg.wce != 0);
}
static uint32_t virtio_blk_get_features(VirtIODevice *vdev, uint32_t features)
{
VirtIOBlock *s = to_virtio_blk(vdev);
features |= (1 << VIRTIO_BLK_F_SEG_MAX);
features |= (1 << VIRTIO_BLK_F_GEOMETRY);
features |= (1 << VIRTIO_BLK_F_TOPOLOGY);
features |= (1 << VIRTIO_BLK_F_BLK_SIZE);
features |= (1 << VIRTIO_BLK_F_SCSI);
if (s->blk->config_wce) {
features |= (1 << VIRTIO_BLK_F_CONFIG_WCE);
}
if (bdrv_enable_write_cache(s->bs))
features |= (1 << VIRTIO_BLK_F_WCE);
if (bdrv_is_read_only(s->bs))
features |= 1 << VIRTIO_BLK_F_RO;
return features;
}
static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
{
VirtIOBlock *s = to_virtio_blk(vdev);
uint32_t features;
#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
if (s->dataplane && !(status & (VIRTIO_CONFIG_S_DRIVER |
VIRTIO_CONFIG_S_DRIVER_OK))) {
virtio_blk_data_plane_stop(s->dataplane);
}
#endif
if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
return;
}
features = vdev->guest_features;
bdrv_set_enable_write_cache(s->bs, !!(features & (1 << VIRTIO_BLK_F_WCE)));
}
static void virtio_blk_save(QEMUFile *f, void *opaque)
{
VirtIOBlock *s = opaque;
VirtIOBlockReq *req = s->rq;
virtio_save(&s->vdev, f);
while (req) {
qemu_put_sbyte(f, 1);
qemu_put_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
req = req->next;
}
qemu_put_sbyte(f, 0);
}
static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id)
{
VirtIOBlock *s = opaque;
int ret;
if (version_id != 2)
return -EINVAL;
ret = virtio_load(&s->vdev, f);
if (ret) {
return ret;
}
while (qemu_get_sbyte(f)) {
VirtIOBlockReq *req = virtio_blk_alloc_request(s);
qemu_get_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
req->next = s->rq;
s->rq = req;
virtqueue_map_sg(req->elem.in_sg, req->elem.in_addr,
req->elem.in_num, 1);
virtqueue_map_sg(req->elem.out_sg, req->elem.out_addr,
req->elem.out_num, 0);
}
return 0;
}
static void virtio_blk_resize(void *opaque)
{
VirtIOBlock *s = opaque;
virtio_notify_config(&s->vdev);
}
static const BlockDevOps virtio_block_ops = {
.resize_cb = virtio_blk_resize,
};
VirtIODevice *virtio_blk_init(DeviceState *dev, VirtIOBlkConf *blk)
{
VirtIOBlock *s;
static int virtio_blk_id;
if (!blk->conf.bs) {
error_report("drive property not set");
return NULL;
}
if (!bdrv_is_inserted(blk->conf.bs)) {
error_report("Device needs media, but drive is empty");
return NULL;
}
blkconf_serial(&blk->conf, &blk->serial);
if (blkconf_geometry(&blk->conf, NULL, 65535, 255, 255) < 0) {
return NULL;
}
s = (VirtIOBlock *)virtio_common_init("virtio-blk", VIRTIO_ID_BLOCK,
sizeof(struct virtio_blk_config),
sizeof(VirtIOBlock));
s->vdev.get_config = virtio_blk_update_config;
s->vdev.set_config = virtio_blk_set_config;
s->vdev.get_features = virtio_blk_get_features;
s->vdev.set_status = virtio_blk_set_status;
s->vdev.reset = virtio_blk_reset;
s->bs = blk->conf.bs;
s->conf = &blk->conf;
s->blk = blk;
s->rq = NULL;
s->sector_mask = (s->conf->logical_block_size / BDRV_SECTOR_SIZE) - 1;
s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output);
#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
if (!virtio_blk_data_plane_create(&s->vdev, blk, &s->dataplane)) {
virtio_cleanup(&s->vdev);
return NULL;
}
#endif
s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
s->qdev = dev;
register_savevm(dev, "virtio-blk", virtio_blk_id++, 2,
virtio_blk_save, virtio_blk_load, s);
bdrv_set_dev_ops(s->bs, &virtio_block_ops, s);
bdrv_set_buffer_alignment(s->bs, s->conf->logical_block_size);
bdrv_iostatus_enable(s->bs);
add_boot_device_path(s->conf->bootindex, dev, "/disk@0,0");
return &s->vdev;
}
void virtio_blk_exit(VirtIODevice *vdev)
{
VirtIOBlock *s = to_virtio_blk(vdev);
#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
virtio_blk_data_plane_destroy(s->dataplane);
s->dataplane = NULL;
#endif
qemu_del_vm_change_state_handler(s->change);
unregister_savevm(s->qdev, "virtio-blk", s);
blockdev_mark_auto_del(s->bs);
virtio_cleanup(vdev);
}
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